[TowerTalk] Which Vertical is More Robust ?

[Stan Stockton]

Gedas,

DXE has .120 wall aluminum tubing in the larger sizes that skips every other 1/8" OD size when telescoping.

I would start with 3 feet of 2 inch X .120, then 6 foot pieces of 1.75, 1.5 and 1.25 (all .120 wall) and then 3 foot pieces of every size they have starting with 1 inch down to 3/8.  You won't be using 3 feet of the 3/8". This is good for about 80 mph and will end up weighing about 18 pounds.  

Less expensive and even lighter weight would be to start with a smaller size and use longer lengths of smaller diameter stuff at the top.  How strong do you want it to be?  If the wind speed is more than about 65 MPH at that low height through the trees you probably have bigger problems than a bent 40m vertical.

73... Stan, K5GO



> On Jan 1, 2020, at 10:13 AM, Gedas <w8bya at mchsi.com> wrote:
> 
> HNY to all !
> 
> I cannot think of a better time to start a new 40m phased vertical project then the dead of winter with snow on the ground (as usual I could not get to it during the summer or fall).
> 
> Anyway, I have drawn up two possibilities for a pair of 33' self supporting verticals. Both start out with a 10' length of EMT but one choice starts out with a larger dia then the other before I switch over to tapering aluminum sections.
> 
> A) Starts out with a 10' length of 1-1/4" EMT followed by tapering 5' sections of aluminum tubing (4' long exposed, 1' inside the previous lower section) until the very top length section which will be 3/4" OD dia. These will be standard DX engineering aluminum tubes.
> 
> B) Starts out with a 10' length of 1-1/2" EMT, then a 5' length of 1-1/4" dia of EMT (4' long exposed, 1' inside the previous section of EMT) then followed by tapering 5' sections of aluminum tubing as above. The only difference being this choice would end up using 1" aluminum tubing as the very top piece.
> 
> So the obvious difference between the two are that choice A) uses just one length of thinner EMT and overall thinner aluminum tubing sections to the top while choice B) uses 2 lengths of larger dia EMT and then larger dia aluminum tubing to the very top.
> 
> I do not have the software to analyze choice A) vs. choice B) in a high wind situation. I am uncertain if the stronger, larger dia tubing with it's higher wind load will be a plus or a minus in the end to it's overall strength. Any thoughts or comments on which one will survive better during heavy wind conditions? TU
> 
> Gedas, W8BYA
> 
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